Phonograph.



Patentelj May 2|, 1901.

A. L. DUWELIUS'.

PHDNOGRAPH.

(Application filed June 20, 1898.) (No Model.) 4 Sheets-Sheet l.

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PHUNOGB'APl-l.

(Application am June 20, 1595.

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No. 674,575. Patented May 2|, 190i.

A. L. DUWELIUS.

PHONOGRAPH.

(Application filed June 20, 1898.) (No Model.) I 4Sheats-Sheet 3.

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No. 674,575. Patented May 2|, I90l. A. L. DUWELIUSL PHONOGRAPH.

(Application filed June 20, 1898.)

(No Model.) 4 Sheets-Sheet 4.

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' UNITED STATES PATENT FFICE.

AUGUSTUS L. DUYVELIUS, OF CINCINNATI, OHIO, ASSIGNOR TO ALFRED H. DUWELIUS AND WALTER S. DUVVELIUS, OF SAME PLACE.

PHONOGRAPH.

SPECIFICATION forming part of Letters Patent No. 674,575, dated May 21, 1901.

Application filed June 20, 1898. Serial No. 683,979- (No model.)

T at whom it may concern:

Be it known that I, AUGUSTUS L. DUWE- LIUs, a citizen of the United States, residing at Cincinnati, county of Hamilton, State of Ohio, have invented certain new and useful Improvements in the Art of Reproducing Sound; and I do hereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others to skilled in the art to which it appertains to make and use the same.

My invention relates to certain new and useful improvements in the art of reproducing sound; and it has for its objeetto provide means for obtaining a more nearly perfect reproduction of sound than has been heretofore attainable. I use the term reproduction in its general sense as including the entire operation of reproduction from the ini- 2o tial step of receiving and recording the sound to the final step of receiving and rendering it again audible.

It is Well known that the loudness of sound produced by a vibrating diaphragm is dependent upon the amplitude of vibration of the diaphragm. Heretofore in the construction of sound-reproducing devices the practieehas been in accordance With this law of physics to increase or diminish the amplio tude of vibration of the receiving-diaphragm according as it was desired to increase or diminish the volume of the reproduced sound. I have discovered, however, that in dealing with complex sounds of varying volume,

5 quality of tone or timbre, and distinctness of articulation-such, for instance, as the articulations of the human voice-better results are obtained by providing a diaphragm having a total mean effective area of not less than three and a half square inches. It has also been the general practice in the construction of the speaking-trumpets employed as sound-ducts between the diaphragm and the atmosphere to give them substantially 5 the form of a cone terminating at its smaller end in a neck provided with a throat much smaller in area than the area of the diaphragm. I have found that much better results are obtained by providing a throat having an area of not less than nine-sixteenths of the area of the vibrating portion of the diaphragm, and also that when the throat is so constructed as to admit of a variation of its length pleasing effects may be prod need, sometimes to the extent of materially improving the reproduction of badly-recorded sound. I have further discovered that by providing a tubular extension to the reverse side of the diaphragm-holder the sonorousness of the apparatus may be still further increased. This circumstance I attribute to the fact that the tubular extension contains a relatively deep column of air, confined at the sides but, establishing practically-unobstrueted communication between the diaphragm and the external air at the end of the tubular extension, that it acts as a resonator varying the sharpness or hollowness of the tone, and that it serves, in combination with the tubular extension or throat on the obverse side of the diaphragm, to establish sonorous zones or sound-waves remote from the apparatus by causing positive vibrations synchronous with the reciprocating movements of both sides of the diaphragm, and producing thereby positive alternate compressions and rarefactions of the atmosphere in contact with the tympanum of the ear. I have further discovered that by placing the diaphragm in a vertical position a more perfect reproduction of sound is obtained.

Another feature of my invention relates particularly to the recording step in the general operation of sound reproduction. Heretofore it has been customary to record the sound-vibrations upon a revolving cylinder or disk of wax or like material having a soft surface, through the agency of a gouge actuated by the diaphragm to produce indensequent clearness greatly enhanced. This feature of my invention consists, generally speaking, in the employment of a revolving cutter or abrader guided and controlled by the vibrating diaphragm, so that the diaphragm instead of supplying the power necessary to engrave merely regulates the depth of the cut.

My invention is applicable generally to sound-reproducing devices, and particularly to the phonograph, graphophone, gramophone, and the like, as will be readily understood.

In the accompanying drawings, Figure 1 represents a plan view of my improved diaphragm and holder. Fig. 2 represent-s a sectional view of the diaphragm and holder and their adjuncts partly in elevation. Fig. 3 represents an end view, partly in section, of a phonograph equipped with my improved diaphragm and holder and record-engraving device. Fig. 4 represents, on a larger scale, one form of my revolving cutter-tool. Fig. 5 represents, in section and on a larger scale, the preferred means for connecting the shank of the revolving cutter with the flexible driving-shaft. Fig. 6 represents a central sectional view of my improved diaphragm and holder, the tubular extension, and the adjustable sound duct. Fig. 7 represents a modified form of the sound-duct. Fig. 8 represents a form of my apparatus in which the diaphragm d and its holder h are employed in a vertical position, the connection with the links Z being made through a bell-crank or angle lever Z, fulcrumed on the holder h. In the form shown sound-ducts with tubular throats w 00 are applied to both sides of the diaphragm-holder.

Similarletters of reference indicate similar parts throughout the several views.

Referring to the drawings, and particularly to Figs. 1 and 2 thereof, 3 indicates the rotatory shaft of the phonograph, driven from any suitable source of power and provided with the customary mandrel m. 0 indicates the record-cylinder; r, the reproducing-stylus and fulcru med carriergf, the floating fulcrum and weight; a, the speaker-arm support; a the adjusting-screws, and I the rail upon which the adj usting-screws are adapted to ride. All of these parts being well known in the art, their construction and mode of operation will be readily understood.

Attached to the speaker arm or support a is shown my diaphragm-holder h, clamping the rim of the diaphragm d, the tension of which is regulated by the screw 71. and washer h together with the circular bridge h. 0n the face of the diaphragm d, but eccentric thereto, is shown the relatively non-flexible area g, connected with the stylus-carrier r by the link Z. This non-flexible area may be produced by adding a stiff disk to either side of the diaphragm, as shown, or may be produced by corrugating or embossing the diaphragm itself or by scoring it, or in many other Ways and forms. The rat-i0 of the nonflexible to the flexible area of the diaphragm will depend upon the nature of the materials employed, but should be as great as permissible in order to produce vibration over the largest area possible.

By locating the non-flexible area in a position eccentric to the main portion of the diaphragm the practical effect is to impart a different kind of movement thereto and to produce better results. Thus when so located the resistance to its movement becomes unequal and that port-ion of its periphery and surface nearest the edge or rim of the diaphragm offers the greatest resistance to motion and becomes relatively to a greater or less extent (depending upon the degree of eccentricity) a fulcrum. In other words, the non-flexible area becomes in effect a musical reed.

As shown in Fig. 6, the diaphragm-holder is preferably provided at the reverse side of the diaphragm with a tubular extension 71 serving as a resonator and containing a comparatively deep column of air in communication with the external atmosphere and confined at its sides. The sound-duct is provided with a throat 00, preferably of approximately the same size as the diaphragm, but which should in any event not be less in area than nine-sixteenths of the vibrating portion of the diaphragm. In order to vary the effect, the neck n of the sound-duct is made adjustable in length, preferably by constructingit of a number of sections telescoping within one another. I have found by experiment that for most sounds a length of tube or throat approximately equal to its diameter is most desirable. In the form shown in Fig. 6 the sound-duct is adapted to project the sound vertically, while in the form shown in Fig. 7 it is intended to project the sound horizontally.

The means for obtaining the permanent record constituting a feature of my invention are illustrated in Fig. 3, one of the forms of cutting-tool or abrader being shown in Figs.

Land 5. The cutting-tool 7a, which is designed to revolve rapidly, is journaled in a carrier e and is driven by a shaft .9 through the instrumentality of the friction-gears p q, the flexible shaftt, and the coupling u. The ends of the flexible shaft 15 are journaled in bearings 0 '0 The form of flexible coupling u shown consists of a flexible diaphragm it, having its rim clamped in a recessed case 2L2, which is joined to and driven by the flexible shaft 25. Attached to the center of this diaphragm by means of the nut 11, is the tool-socket u through which the necessary engagement with the shank of the cutting-tool is made. The

it to move freely in a vertical direction, but prevent all horizontal movement. The toolcarrier 6 is provided With the extended arm e which through the linkl makes connection with the diaphragm by which the vertical movement of the cutting-toolis controlled.

At the extreme end of the arm e is shown connected therewith a spiral spring e carrying a suspended weight a. The purpose of this combination of weight and spring is to furnish the necessary pressure to the cuttingtool responsively to the variations of the diaphragm d and to avoid chattering. The maximum depth of cutting may be regulated by the screws 61?. The angle of cutting may be altered, as required, by slightly Withdrawing the bearing 4; and lowering the tool by means of the screw (1 The operation of the devices is such that the rotation of the cylinder 0 against the rapidly-revolving cutter it causes the surface of the cylinder to be scored to such depths as the variations of the diaphragm d, actuated by the impinging sound- Waves, may permit.

Having thus described my said invention, what I claim is 1. In a sound-reproducing apparatus, a vibratory diaphragm having a substantially non-flexible area eccentric thereto.

2. In a sound-reproducing apparatus, the combination With a vibratory diaphragm having a non-flexible area eccentric thereto, of a sound-duct having an adjustable throat leading to said diaphragm.

3. In a sound-recording apparatus, the combination with a record-surface, a cutting or abrading tool rotatable on an axis substantially parallel to the direction of movement of said surface at the point of engagement with said tool, of means for rotating the same, and a diaphragm for vibrating and governing the depth of cut of the tool in accordance with the diaphragm vibrations.

4:. ha sound-reproducing apparatus, the combination with a cutting or abrading tool, of means for rotating it, a vibratory diaphragm having a portion of inferior flexibility connected to said cutting or abrading tool to govern the depth of cut thereof.

5. In a sound-reproducing apparatus, the combination of a vibratory diaphragm having an area of inferior flexibility eccentric to the diaphragm as a whole, and an air-column chamber on the reverse side of said diaphragm.

In testimony whereof I afl'iX my signature in presence of two Witnesses.

AUGUSTUS L. DUWELIUS.

Witnesses:

LEONARD W. Goss, ARoH. MIRRIELEES. 

